+++ /dev/null
-/*
- * linux/drivers/i2c/busses/i2c-nuc900.c
- *
- * Copyright (c) 2010 Nuvoton technology corporation.
- *
- * This driver based on S3C2410 I2C driver of Ben Dooks <ben-Y5A6D6n0/KfQXOPxS62xeg@public.gmane.org>.
- * Written by Wan ZongShun <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation;version 2 of the License.
- *
- */
-
-#include <linux/kernel.h>
-#include <linux/module.h>
-
-#include <linux/i2c.h>
-#include <linux/init.h>
-#include <linux/time.h>
-#include <linux/interrupt.h>
-#include <linux/delay.h>
-#include <linux/errno.h>
-#include <linux/err.h>
-#include <linux/platform_device.h>
-#include <linux/clk.h>
-#include <linux/cpufreq.h>
-#include <linux/slab.h>
-#include <linux/io.h>
-
-#include <mach/mfp.h>
-#include <linux/platform_data/i2c-nuc900.h>
-
-/* nuc900 i2c registers offset */
-
-#define CSR 0x00
-#define DIVIDER 0x04
-#define CMDR 0x08
-#define SWR 0x0C
-#define RXR 0x10
-#define TXR 0x14
-
-/* nuc900 i2c CSR register bits */
-
-#define IRQEN 0x003
-#define I2CBUSY 0x400
-#define I2CSTART 0x018
-#define IRQFLAG 0x004
-#define ARBIT_LOST 0x200
-#define SLAVE_ACK 0x800
-
-/* nuc900 i2c CMDR register bits */
-
-#define I2C_CMD_START 0x10
-#define I2C_CMD_STOP 0x08
-#define I2C_CMD_READ 0x04
-#define I2C_CMD_WRITE 0x02
-#define I2C_CMD_NACK 0x01
-
-/* i2c controller state */
-
-enum nuc900_i2c_state {
- STATE_IDLE,
- STATE_START,
- STATE_READ,
- STATE_WRITE,
- STATE_STOP
-};
-
-/* i2c controller private data */
-
-struct nuc900_i2c {
- spinlock_t lock;
- wait_queue_head_t wait;
-
- struct i2c_msg *msg;
- unsigned int msg_num;
- unsigned int msg_idx;
- unsigned int msg_ptr;
- unsigned int irq;
-
- enum nuc900_i2c_state state;
-
- void __iomem *regs;
- struct clk *clk;
- struct device *dev;
- struct resource *ioarea;
- struct i2c_adapter adap;
-};
-
-/* nuc900_i2c_master_complete
- *
- * complete the message and wake up the caller, using the given return code,
- * or zero to mean ok.
-*/
-
-static inline void nuc900_i2c_master_complete(struct nuc900_i2c *i2c, int ret)
-{
- dev_dbg(i2c->dev, "master_complete %d\n", ret);
-
- i2c->msg_ptr = 0;
- i2c->msg = NULL;
- i2c->msg_idx++;
- i2c->msg_num = 0;
- if (ret)
- i2c->msg_idx = ret;
-
- wake_up(&i2c->wait);
-}
-
-/* irq enable/disable functions */
-
-static inline void nuc900_i2c_disable_irq(struct nuc900_i2c *i2c)
-{
- unsigned long tmp;
-
- tmp = readl(i2c->regs + CSR);
- writel(tmp & ~IRQEN, i2c->regs + CSR);
-}
-
-static inline void nuc900_i2c_enable_irq(struct nuc900_i2c *i2c)
-{
- unsigned long tmp;
-
- tmp = readl(i2c->regs + CSR);
- writel(tmp | IRQEN, i2c->regs + CSR);
-}
-
-
-/* nuc900_i2c_message_start
- *
- * put the start of a message onto the bus
-*/
-
-static void nuc900_i2c_message_start(struct nuc900_i2c *i2c,
- struct i2c_msg *msg)
-{
- unsigned int addr = (msg->addr & 0x7f) << 1;
-
- if (msg->flags & I2C_M_RD)
- addr |= 0x1;
- writel(addr & 0xff, i2c->regs + TXR);
- writel(I2C_CMD_START | I2C_CMD_WRITE, i2c->regs + CMDR);
-}
-
-static inline void nuc900_i2c_stop(struct nuc900_i2c *i2c, int ret)
-{
-
- dev_dbg(i2c->dev, "STOP\n");
-
- /* stop the transfer */
- i2c->state = STATE_STOP;
- writel(I2C_CMD_STOP, i2c->regs + CMDR);
-
- nuc900_i2c_master_complete(i2c, ret);
- nuc900_i2c_disable_irq(i2c);
-}
-
-/* helper functions to determine the current state in the set of
- * messages we are sending
-*/
-
-/* is_lastmsg()
- *
- * returns TRUE if the current message is the last in the set
-*/
-
-static inline int is_lastmsg(struct nuc900_i2c *i2c)
-{
- return i2c->msg_idx >= (i2c->msg_num - 1);
-}
-
-/* is_msglast
- *
- * returns TRUE if we this is the last byte in the current message
-*/
-
-static inline int is_msglast(struct nuc900_i2c *i2c)
-{
- return i2c->msg_ptr == i2c->msg->len-1;
-}
-
-/* is_msgend
- *
- * returns TRUE if we reached the end of the current message
-*/
-
-static inline int is_msgend(struct nuc900_i2c *i2c)
-{
- return i2c->msg_ptr >= i2c->msg->len;
-}
-
-/* i2c_nuc900_irq_nextbyte
- *
- * process an interrupt and work out what to do
- */
-
-static void i2c_nuc900_irq_nextbyte(struct nuc900_i2c *i2c,
- unsigned long iicstat)
-{
- unsigned char byte;
-
- switch (i2c->state) {
-
- case STATE_IDLE:
- dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
- break;
-
- case STATE_STOP:
- dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
- nuc900_i2c_disable_irq(i2c);
- break;
-
- case STATE_START:
- /* last thing we did was send a start condition on the
- * bus, or started a new i2c message
- */
-
- if (iicstat & SLAVE_ACK &&
- !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
- /* ack was not received... */
-
- dev_dbg(i2c->dev, "ack was not received\n");
- nuc900_i2c_stop(i2c, -ENXIO);
- break;
- }
-
- if (i2c->msg->flags & I2C_M_RD)
- i2c->state = STATE_READ;
- else
- i2c->state = STATE_WRITE;
-
- /* terminate the transfer if there is nothing to do
- * as this is used by the i2c probe to find devices.
- */
-
- if (is_lastmsg(i2c) && i2c->msg->len == 0) {
- nuc900_i2c_stop(i2c, 0);
- break;
- }
-
- if (i2c->state == STATE_READ)
- goto prepare_read;
-
- /* fall through to the write state, as we will need to
- * send a byte as well
- */
-
- case STATE_WRITE:
- /* we are writing data to the device... check for the
- * end of the message, and if so, work out what to do
- */
-
- if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
- if (iicstat & SLAVE_ACK) {
- dev_dbg(i2c->dev, "WRITE: No Ack\n");
-
- nuc900_i2c_stop(i2c, -ECONNREFUSED);
- break;
- }
- }
-
-retry_write:
-
- if (!is_msgend(i2c)) {
- byte = i2c->msg->buf[i2c->msg_ptr++];
- writeb(byte, i2c->regs + TXR);
- writel(I2C_CMD_WRITE, i2c->regs + CMDR);
-
- } else if (!is_lastmsg(i2c)) {
- /* we need to go to the next i2c message */
-
- dev_dbg(i2c->dev, "WRITE: Next Message\n");
-
- i2c->msg_ptr = 0;
- i2c->msg_idx++;
- i2c->msg++;
-
- /* check to see if we need to do another message */
- if (i2c->msg->flags & I2C_M_NOSTART) {
-
- if (i2c->msg->flags & I2C_M_RD) {
- /* cannot do this, the controller
- * forces us to send a new START
- * when we change direction
- */
-
- nuc900_i2c_stop(i2c, -EINVAL);
- }
-
- goto retry_write;
- } else {
- /* send the new start */
- nuc900_i2c_message_start(i2c, i2c->msg);
- i2c->state = STATE_START;
- }
-
- } else {
- /* send stop */
-
- nuc900_i2c_stop(i2c, 0);
- }
- break;
-
- case STATE_READ:
- /* we have a byte of data in the data register, do
- * something with it, and then work out whether we are
- * going to do any more read/write
- */
-
- byte = readb(i2c->regs + RXR);
- i2c->msg->buf[i2c->msg_ptr++] = byte;
-
-prepare_read:
- if (is_msglast(i2c)) {
- /* last byte of buffer */
-
- if (is_lastmsg(i2c))
- writel(I2C_CMD_READ | I2C_CMD_NACK,
- i2c->regs + CMDR);
-
- } else if (is_msgend(i2c)) {
- /* ok, we've read the entire buffer, see if there
- * is anything else we need to do
- */
-
- if (is_lastmsg(i2c)) {
- /* last message, send stop and complete */
- dev_dbg(i2c->dev, "READ: Send Stop\n");
-
- nuc900_i2c_stop(i2c, 0);
- } else {
- /* go to the next transfer */
- dev_dbg(i2c->dev, "READ: Next Transfer\n");
-
- i2c->msg_ptr = 0;
- i2c->msg_idx++;
- i2c->msg++;
-
- writel(I2C_CMD_READ, i2c->regs + CMDR);
- }
-
- } else {
- writel(I2C_CMD_READ, i2c->regs + CMDR);
- }
-
- break;
- }
-}
-
-/* nuc900_i2c_irq
- *
- * top level IRQ servicing routine
-*/
-
-static irqreturn_t nuc900_i2c_irq(int irqno, void *dev_id)
-{
- struct nuc900_i2c *i2c = dev_id;
- unsigned long status;
-
- status = readl(i2c->regs + CSR);
- writel(status | IRQFLAG, i2c->regs + CSR);
-
- if (status & ARBIT_LOST) {
- /* deal with arbitration loss */
- dev_err(i2c->dev, "deal with arbitration loss\n");
- goto out;
- }
-
- if (i2c->state == STATE_IDLE) {
- dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
- goto out;
- }
-
- /* pretty much this leaves us with the fact that we've
- * transmitted or received whatever byte we last sent
- */
-
- i2c_nuc900_irq_nextbyte(i2c, status);
-
- out:
- return IRQ_HANDLED;
-}
-
-
-/* nuc900_i2c_set_master
- *
- * get the i2c bus for a master transaction
-*/
-
-static int nuc900_i2c_set_master(struct nuc900_i2c *i2c)
-{
- int timeout = 400;
-
- while (timeout-- > 0) {
- if (((readl(i2c->regs + SWR) & I2CSTART) == I2CSTART) &&
- ((readl(i2c->regs + CSR) & I2CBUSY) == 0)) {
- return 0;
- }
-
- msleep(1);
- }
-
- return -ETIMEDOUT;
-}
-
-/* nuc900_i2c_doxfer
- *
- * this starts an i2c transfer
-*/
-
-static int nuc900_i2c_doxfer(struct nuc900_i2c *i2c,
- struct i2c_msg *msgs, int num)
-{
- unsigned long iicstat, timeout;
- int spins = 20;
- int ret;
-
- ret = nuc900_i2c_set_master(i2c);
- if (ret != 0) {
- dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
- ret = -EAGAIN;
- goto out;
- }
-
- spin_lock_irq(&i2c->lock);
-
- i2c->msg = msgs;
- i2c->msg_num = num;
- i2c->msg_ptr = 0;
- i2c->msg_idx = 0;
- i2c->state = STATE_START;
-
- nuc900_i2c_message_start(i2c, msgs);
- spin_unlock_irq(&i2c->lock);
-
- timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
-
- ret = i2c->msg_idx;
-
- /* having these next two as dev_err() makes life very
- * noisy when doing an i2cdetect
- */
-
- if (timeout == 0)
- dev_dbg(i2c->dev, "timeout\n");
- else if (ret != num)
- dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
-
- /* ensure the stop has been through the bus */
-
- dev_dbg(i2c->dev, "waiting for bus idle\n");
-
- /* first, try busy waiting briefly */
- do {
- iicstat = readl(i2c->regs + CSR);
- } while ((iicstat & I2CBUSY) && --spins);
-
- /* if that timed out sleep */
- if (!spins) {
- msleep(1);
- iicstat = readl(i2c->regs + CSR);
- }
-
- if (iicstat & I2CBUSY)
- dev_warn(i2c->dev, "timeout waiting for bus idle\n");
-
- out:
- return ret;
-}
-
-/* nuc900_i2c_xfer
- *
- * first port of call from the i2c bus code when an message needs
- * transferring across the i2c bus.
-*/
-
-static int nuc900_i2c_xfer(struct i2c_adapter *adap,
- struct i2c_msg *msgs, int num)
-{
- struct nuc900_i2c *i2c = (struct nuc900_i2c *)adap->algo_data;
- int retry;
- int ret;
-
- nuc900_i2c_enable_irq(i2c);
-
- for (retry = 0; retry < adap->retries; retry++) {
-
- ret = nuc900_i2c_doxfer(i2c, msgs, num);
-
- if (ret != -EAGAIN)
- return ret;
-
- dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
-
- udelay(100);
- }
-
- return -EREMOTEIO;
-}
-
-/* declare our i2c functionality */
-static u32 nuc900_i2c_func(struct i2c_adapter *adap)
-{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART |
- I2C_FUNC_PROTOCOL_MANGLING;
-}
-
-/* i2c bus registration info */
-
-static const struct i2c_algorithm nuc900_i2c_algorithm = {
- .master_xfer = nuc900_i2c_xfer,
- .functionality = nuc900_i2c_func,
-};
-
-/* nuc900_i2c_probe
- *
- * called by the bus driver when a suitable device is found
-*/
-
-static int nuc900_i2c_probe(struct platform_device *pdev)
-{
- struct nuc900_i2c *i2c;
- struct nuc900_platform_i2c *pdata;
- struct resource *res;
- int ret;
-
- pdata = dev_get_platdata(&pdev->dev);
- if (!pdata) {
- dev_err(&pdev->dev, "no platform data\n");
- return -EINVAL;
- }
-
- i2c = kzalloc(sizeof(struct nuc900_i2c), GFP_KERNEL);
- if (!i2c) {
- dev_err(&pdev->dev, "no memory for state\n");
- return -ENOMEM;
- }
-
- strlcpy(i2c->adap.name, "nuc900-i2c0", sizeof(i2c->adap.name));
- i2c->adap.owner = THIS_MODULE;
- i2c->adap.algo = &nuc900_i2c_algorithm;
- i2c->adap.retries = 2;
- i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
-
- spin_lock_init(&i2c->lock);
- init_waitqueue_head(&i2c->wait);
-
- /* find the clock and enable it */
-
- i2c->dev = &pdev->dev;
- i2c->clk = clk_get(&pdev->dev, NULL);
- if (IS_ERR(i2c->clk)) {
- dev_err(&pdev->dev, "cannot get clock\n");
- ret = -ENOENT;
- goto err_noclk;
- }
-
- dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
-
- clk_enable(i2c->clk);
-
- /* map the registers */
-
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (res == NULL) {
- dev_err(&pdev->dev, "cannot find IO resource\n");
- ret = -ENOENT;
- goto err_clk;
- }
-
- i2c->ioarea = request_mem_region(res->start, resource_size(res),
- pdev->name);
-
- if (i2c->ioarea == NULL) {
- dev_err(&pdev->dev, "cannot request IO\n");
- ret = -ENXIO;
- goto err_clk;
- }
-
- i2c->regs = ioremap(res->start, resource_size(res));
-
- if (i2c->regs == NULL) {
- dev_err(&pdev->dev, "cannot map IO\n");
- ret = -ENXIO;
- goto err_ioarea;
- }
-
- dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
- i2c->regs, i2c->ioarea, res);
-
- /* setup info block for the i2c core */
-
- i2c->adap.algo_data = i2c;
- i2c->adap.dev.parent = &pdev->dev;
-
- mfp_set_groupg(&pdev->dev, NULL);
-
- clk_get_rate(i2c->clk);
-
- ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1;
- writel(ret & 0xffff, i2c->regs + DIVIDER);
-
- /* find the IRQ for this unit (note, this relies on the init call to
- * ensure no current IRQs pending
- */
-
- i2c->irq = ret = platform_get_irq(pdev, 0);
- if (ret <= 0) {
- dev_err(&pdev->dev, "cannot find IRQ\n");
- goto err_iomap;
- }
-
- ret = request_irq(i2c->irq, nuc900_i2c_irq, IRQF_SHARED,
- dev_name(&pdev->dev), i2c);
-
- if (ret != 0) {
- dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
- goto err_iomap;
- }
-
- /* Note, previous versions of the driver used i2c_add_adapter()
- * to add the bus at any number. We now pass the bus number via
- * the platform data, so if unset it will now default to always
- * being bus 0.
- */
-
- i2c->adap.nr = pdata->bus_num;
-
- ret = i2c_add_numbered_adapter(&i2c->adap);
- if (ret < 0) {
- dev_err(&pdev->dev, "failed to add bus to i2c core\n");
- goto err_irq;
- }
-
- platform_set_drvdata(pdev, i2c);
-
- dev_info(&pdev->dev, "%s: NUC900 I2C adapter\n",
- dev_name(&i2c->adap.dev));
- return 0;
-
- err_irq:
- free_irq(i2c->irq, i2c);
-
- err_iomap:
- iounmap(i2c->regs);
-
- err_ioarea:
- release_resource(i2c->ioarea);
- kfree(i2c->ioarea);
-
- err_clk:
- clk_disable(i2c->clk);
- clk_put(i2c->clk);
-
- err_noclk:
- kfree(i2c);
- return ret;
-}
-
-/* nuc900_i2c_remove
- *
- * called when device is removed from the bus
-*/
-
-static int nuc900_i2c_remove(struct platform_device *pdev)
-{
- struct nuc900_i2c *i2c = platform_get_drvdata(pdev);
-
- i2c_del_adapter(&i2c->adap);
- free_irq(i2c->irq, i2c);
-
- clk_disable(i2c->clk);
- clk_put(i2c->clk);
-
- iounmap(i2c->regs);
-
- release_resource(i2c->ioarea);
- kfree(i2c->ioarea);
- kfree(i2c);
-
- return 0;
-}
-
-static struct platform_driver nuc900_i2c_driver = {
- .probe = nuc900_i2c_probe,
- .remove = nuc900_i2c_remove,
- .driver = {
- .owner = THIS_MODULE,
- .name = "nuc900-i2c0",
- },
-};
-
-static int __init i2c_adap_nuc900_init(void)
-{
- return platform_driver_register(&nuc900_i2c_driver);
-}
-
-static void __exit i2c_adap_nuc900_exit(void)
-{
- platform_driver_unregister(&nuc900_i2c_driver);
-}
-subsys_initcall(i2c_adap_nuc900_init);
-module_exit(i2c_adap_nuc900_exit);
-
-MODULE_DESCRIPTION("NUC900 I2C Bus driver");
-MODULE_AUTHOR("Wan ZongShun, <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:nuc900-i2c0");
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff